Herpes Simplex Virus (HSV) is a common cause of infections of the skin and mucus membranes. HSV is one of the most difficult viruses to control and has plagued mankind for thousands of years. HSV infection is typically manifested by painful, blister-like lesions or sores on the mouth or face (oral herpes) or in the genital area (genital herpes). While rarely fatal, herpes sores can be quite painful and unsightly and may cause embarrassment to the infected person.
There are two distinct types of Herpes Simplex Virus, Herpes Simplex Virus 1 (HSV-1) and Herpes Simplex Virus 2 (HSV-2). HSV-1 and HSV-2 are very similar. They can occur separately or can infect the same individual. HSV-1 is generally associated with oral herpes and HSV-2 is generally associated with genital herpes. It is now known, however, that HSV-2 can cause oral herpes and HSV-1 can cause genital herpes.
HSV enters the body through the skin or mucus membranes following contact with an infected person. The virus penetrates vulnerable cells in the lower layers of the skin and attempts to replicate itself in the cell nuclei. In many cases, HSV never causes symptoms to occur. However, if HSV's replication process destroys the host cells, symptoms in the form of sores, ulcers, and fluid-filled blisters may appear. The sores from the primary infection eventually heal without scarring. However, the virus that caused the infection remains in the body and migrates through branches of nerve cells to clusters at the nerve cell ends called the ganglia. The virus persists in the ganglia in a latent state, during which viral replication does not occur. While the virus is latent, symptoms of the virus do not appear. After remaining dormant for some time, the virus may again begin to replicate, causing a recurrent infection. Recurrent infections of HSV tend to be milder than primary infections and can be set off by a variety of factors, including illness and stress. For some persons infected with herpes virus, recurrent infections may be frequent. Approximately 20% to 40% of persons with HSV-1 experience recurrent outbreaks. For persons infected with HSV-2, the recurrence rate is up to 80%.
Scientists are getting closer to decoding the genetic structure of herpes virus. At the present time, however, there is no known cure for herpes. Therefore, there remains a need for new drugs and therapies that ameliorate the symptoms of recurrent outbreaks of HSV.